System and Method for Controlling a Powertrain System of a Vehicle

The disclosure relates generally to the field of controlling a powertrain system of a vehicle, while the vehicle is moving, and, more specifically, to an automatically controlled powertrain system for vehicles. In particular aspects, the disclosure relates to a computer system, powertrain system, vehicle and methods for controlling an engine of a vehicle, while the vehicle is moving. The disclosure can be applied to any type of vehicle, including heavy-duty vehicles, such as trucks, buses, and construction equipment, among other vehicle types. Although the disclosure may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle.

Conventional internal combustion engine vehicles operate continuously when the engine is running, even when idling at traffic lights, stuck in traffic, or during extended periods of inactivity. This constant engine operation results in unnecessary fuel consumption and increased emissions, contributing to environmental pollution and increased fuel costs for vehicle owners. To address these issues, various stop and start technologies have been developed, such as engine idle stop-start systems, which shut off the engine when the vehicle is stationary and automatically restart it when the driver releases the brake or engages the accelerator.

In recent years, there has been a growing demand for more sophisticated and intelligent engine stop-and-start systems for heavy-duty vehicles that can adapt to a wider range of driving conditions. The development of automatic and predictive engine stop-and-start systems addresses these challenges by incorporating predictive algorithms, real-time data sources, and advanced control strategies. Automatic and predictive engine stop-and-start systems aim to provide smoother, more efficient, and less intrusive engine stop-and-start experiences for drivers while increasing fuel savings and emissions reduction.

However, in connection with the use of such systems in a vehicle, such as a heavy-duty vehicle, there is still a need for further improving the operations of the powertrain system, while the vehicle is moving.

According to a first aspect of the disclosure, there is provided a computer system for controlling a powertrain system of a vehicle. The powertrain system comprises an internal combustion engine connectable to one or more drive wheels. The computer system comprises processing circuitry configured to selectively operate the powertrain system in a number of operational modes, comprising at least a freewheeling mode, in which an output shaft of the engine is non-rotating, and the engine is disconnected from the one or more drive wheels. The processing circuitry is further configured to predict fuel saving in response to a potential up-coming freewheeling mode period, the fuel saving being determined from engine-idle fuel consumption data; predict a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch; predict fuel consumption needed to regain the predicted loss of kinetic energy; compare the predicted fuel saving with the predicted fuel consumption; determine to control the powertrain system into the freewheeling mode based on the comparison; and control the powertrain system into the freewheeling mode.

The first aspect of the disclosure may seek to enhance fuel efficiency in vehicles with powertrain systems configured to be operated in a freewheeling mode with the engine shutdown while the vehicle is in motion, More specifically, the disclosure may seek to managing the challenge of minimizing, or at least reducing, fuel consumption while maintaining operational efficiency and vehicle responsiveness, particularly focusing on the implementation of a freewheeling mode where the internal combustion engine is temporarily shut down and disconnected from the drive wheels to reduce fuel consumption during periods when propulsion is not needed.

A technical benefit may include enhanced fuel efficiency through a more precise management of the freewheeling mode of the powertrain system, in which the proposed computer system provides for predicting when to engage and disengage the freewheeling mode based on the above various dynamic factors to ensure that the benefits of reduced fuel consumption are not offset by the energy costs associated with restarting the engine. By facilitating the timing and conditions under which the freewheeling mode is engaged, the system may minimize, or at least reduce the potential energy loss and mechanical wear associated with frequent transitions between the operational mode, thereby enhancing the overall efficiency and longevity of the powertrain system.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to, based on the comparison of the predicted fuel saving with the predicted fuel consumption, determine to control the powertrain system into the freewheeling mode if the predicted fuel saving is greater than the predicted fuel consumption. A technical benefit may include providing an increased likelihood of improved fuel efficiency by ensuring that the computer system only engages freewheeling mode when there is a determined net fuel saving. This configuration of controlling the powertrain system may be useful in situations where there is a desire to provide a margin on the fuel savings side because shutting down the engine may occasionally wear on the mechanical parts of the powertrain system.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to, based on the comparison of the predicted fuel savings with the predicted fuel consumption, determine a minimum time for the freewheeling mode to achieve a break-even level between fuel saving and fuel consumption. A technical benefit may include fine-tuning the freewheeling duration to maximize fuel savings while minimizing the energy cost of restarting the engine, ensuring an efficient balance between fuel conservation and vehicle readiness.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to predict a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch by predicting loss of kinetic energy occurring from a braking torque on a drive axle coupled to the one or more drive wheels. A technical benefit may include providing a more precise management of kinetic energy loss and recovery, which may enhance the overall energy efficiency of the vehicle and further contribute to smoother transitions between driving modes.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to predict a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch by predicting vehicle speed at the moment of exiting freewheeling mode using the controllable clutch to restart the engine. A technical benefit may include enabling the system to more accurately anticipate the energy needed for re-engagement of the engine, thereby ensuring a smoother and more efficient transition from freewheeling mode to powered mode, which could enhance driving comfort and fuel efficiency.

Optionally in some examples, including in at least one preferred example, the vehicle speed at the moment of exiting freewheeling mode using the controllable clutch to restart the engine may be predicted from topography data. A technical benefit may include the adaptive management of the powertrain system based on anticipated road conditions, which can further enhance fuel savings and reduce emissions by adjusting operational modes in anticipation of changes in the driving environment.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to predict a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch by from data indicative of an engine efficiency level. A technical benefit may include the tailored management of the freewheeling mode to the specific characteristics of the engine, enhancing energy efficiency of the powertrain system by considering the performance metrics of the engine.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to predict a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch from data indicative of total weight of the vehicle. A technical benefit may include further improving the precision in determining the suitability for operating the powertrain system into the freewheeling mode based on vehicle load, which can be particularly advantageous for vehicles that carry variable weights, ensuring enhanced fuel efficiency under varying conditions.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be further configured to predict a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch from data indicative of a predicted total gear ratio at engine restart. A technical benefit may include further improving the precision in determining the suitability for controlling the powertrain system into the freewheeling mode based on the gear selection process upon restarting the engine from the freewheeling mode, thereby ensuring a match between the power demand and the output capability for efficient acceleration and minimal, or at least lower fuel consumption.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be further configured to predict a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch from data indicative of predicted clutch torque and time duration of the clutch engagement for the engine restart. A technical benefit may include enhanced control over the clutch engagement process, leading to smoother operation and reduced wear on the powertrain components, thereby increasing the longevity of the mechanical systems and reducing maintenance costs.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be further configured to predict a potential operational mode for the powertrain system after the freewheeling mode so as to determine whether the engine is to be used for propulsion or for an engine braking operation. A technical benefit may include the possibility of evaluating the subsequent use of the powertrain system after the freewheeling mode when controlling the powertrain system, thus further enhancing vehicle safety and operational efficiency by effectively managing the transition between different operational modes.

Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to control the powertrain system into the freewheeling mode by changing a rotating state of the output shaft to a non-rotating state, and disconnecting the engine from the one or more drive wheels. A technical benefit may include providing improved fuel efficiency and decreased wear on engine components over time.

Optionally in some examples, including in at least one preferred example, the processing circuitry may further be configured to initiate activation of the freewheeling mode based on topography data and vehicle data. A technical benefit may include providing a more precise activation of the freewheeling mode so as to further enhance fuel savings, while minimizing, or at least reducing the risk of disruptions to the driving experience.

Optionally in some examples, including in at least one preferred example, the processing circuitry may further be configured to determine a starting point in time for the freewheeling mode based on topography data and vehicle data. A technical benefit may include further assisting in achieving enhanced fuel efficiency by ensuring that the vehicle takes increased advantage of gravitational forces and inertia during downhill sections of a route.

According to a second aspect of the disclosure, there is provided a powertrain system comprising the computer system according to the first aspect, an internal combustion engine, a controllable clutch, a transmission arranged to be coupled to the internal combustion engine by means of the controllable clutch, and wherein the transmission further comprises an output shaft configured to be coupled to a drive axle of a set of wheels.

The disclosure according to the second aspect may seek to enhance fuel efficiency in vehicles with powertrain systems configured to be operated in a freewheeling mode with the engine shutdown while the vehicle is in motion, More specifically, the disclosure may seek to managing the challenge of minimizing, or at least reducing, fuel consumption while maintaining operational efficiency and vehicle responsiveness, particularly focusing on the implementation of a freewheeling mode where the internal combustion engine is temporarily shut down and disconnected from the drive wheels to reduce fuel consumption during periods when propulsion is not needed. A technical benefit may include enhanced fuel efficiency through a more precise management of the freewheeling mode of the powertrain system, in which the proposed computer system provides for predicting when to engage and disengage the freewheeling mode based on the above various dynamic factors to ensure that the benefits of reduced fuel consumption are not offset by the energy costs associated with restarting the engine. By facilitating the timing and conditions under which the freewheeling mode is engaged, the system may minimize, or at least reduce the potential energy loss and mechanical wear associated with frequent transitions between the operational mode, thereby enhancing the overall efficiency and longevity of the powertrain system.

According to a third aspect of the disclosure, there is provided a vehicle comprising the computer system of the first aspect and/or a powertrain system according to the second aspect. By way of example, the vehicle is a heavy-duty vehicle.

Optionally in some examples, including in at least one preferred example, the vehicle is an internal combustion engine vehicle (ICEV). An ICEV is a vehicle that relies solely on an internal combustion engine for propulsion, without the assistance of electric motors or fuel cells that are characteristic of hybrid or fully electric vehicles. Optionally in some examples, including in at least one preferred example, the vehicle is a non-electric vehicle. In this context, the term non-electric vehicle refers to a vehicle avoid of any electric storage and power system configured to provide traction power to the vehicle. Such electric storage system may be battery system in combination with an electric machine and/or fuel cell system in combination with an electric machine. In other words, a non-electric vehicle is a vehicle comprising the internal combustion engine as the primary, or the only, power source for the powertrain system. The use of the computer system for controlling a non-electric vehicle, while the vehicle is moving, may be particularly useful where the internal combustion engine is the only available power source for the vehicle.

According to a fourth aspect of the disclosure, there is provided a computer-implemented method for controlling a powertrain system of a vehicle, the powertrain system comprising an internal combustion engine connectable to one or more drive wheels, the powertrain system being operable in a number of operational modes, including at least a freewheeling mode FM, in which an output shaft of the engine is non-rotating, and the engine is disconnected from the one or more drive wheels, wherein the method comprises: predicting fuel saving in response to a potential up-coming freewheeling mode period, the fuel saving being determined from engine-idle fuel consumption data; predicting a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch; predicting fuel consumption needed to regain the predicted loss of kinetic energy; comparing the predicted fuel saving with the predicted fuel consumption; determining to control the powertrain system into the freewheeling mode based on the comparison; and controlling the powertrain system into the freewheeling mode.

The disclosure according to the fourth aspect may seek to enhance fuel efficiency in vehicles with powertrain systems configured to be operated in a freewheeling mode with the engine shutdown while the vehicle is in motion, More specifically, the disclosure may seek to managing the challenge of minimizing, or at least reducing, fuel consumption while maintaining operational efficiency and vehicle responsiveness, particularly focusing on the implementation of a freewheeling mode where the internal combustion engine is temporarily shut down and disconnected from the drive wheels to reduce fuel consumption during periods when propulsion is not needed. A technical benefit may include enhanced fuel efficiency through a more precise management of the freewheeling mode of the powertrain system, in which the proposed computer system provides for predicting when to engage and disengage the freewheeling mode based on the above various dynamic factors to ensure that the benefits of reduced fuel consumption are not offset by the energy costs associated with restarting the engine. By facilitating the timing and conditions under which the freewheeling mode is engaged, the system may minimize, or at least reduce the potential energy loss and mechanical wear associated with frequent transitions between the operational mode, thereby enhancing the overall efficiency and longevity of the powertrain system.

According to a fifth aspect of the disclosure, there is provided a computer program product comprising program code for performing, when executed by the processing circuitry of the first aspect, the method of the fourth aspect.

According to a sixth aspect of the disclosure, there is provided a non-transitory computer-readable storage medium comprising instructions, which when executed by the processing circuitry of the first aspect, cause the processing circuitry to perform the method of fourth aspect.

The disclosed aspects, examples (including any preferred examples), and/or accompanying claims may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the disclosure as described herein.

There are also disclosed herein computer systems, control units, code modules, computer-implemented methods, computer readable media, and computer program products associated with the above discussed technical benefits.

The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.

In the field of vehicles, there is an increasing demand for improving the fuel efficiency and reducing emissions of the internal combustion engine (ICE). One operation for enhancing fuel efficiency and lowering emissions in a powertrain system is referred to as freewheeling. Freewheeling is commonly applied in heavy-duty vehicles. The purpose of freewheeling in heavy-duty vehicles is to save fuel and reduce engine load under certain driving conditions. Freewheeling is commonly used when the vehicle is descending downhill or traveling on a slope. There are typically two types of freewheeling modes. In one type of freewheeling operation, the engine is disconnected or disengaged from the driving wheel(s), allowing the vehicle to coast freely (in contrast to a conventional coasting mode). Hereby, the heavy-duty vehicle can take advantage of gravitational forces to maintain or increase speed while consuming minimal fuel. This type of freewheeling operation can be particularly useful for improving fuel efficiency and reducing wear and tear on the braking system during downhill descents. Freewheeling can be engaged manually by the driver or automatically by the vehicle's control system, e.g. as a part of the automatic and predictive engine stop-and-start system. When the driver and/or an automatic vehicle control system initiates freewheeling, the transmission is typically shifted to a neutral or coasting position, decoupling the engine from the drivetrain. In some cases, the engine may idle at a minimal RPM to maintain essential functions like power steering and braking. This mode of operation may be denoted as a freewheeling mode with the engine disconnected.

Freewheeling may also include a specific mode of operation where the engine is typically shutdown (in addition to being disconnected from the driving wheels). M ore specifically, in the context of the present disclosure, this freewheeling mode refers to an operational mode in which the output shaft of the engine is non-rotating, and the engine is disconnected from the one or more drive wheels. An operational mode where the output shaft of the engine is non-rotating typically signifies that the engine is in a non-active state, such as in a shutdown state, engine off state, standby mode. By way of example, in such freewheeling mode, the engine is thus shutdown, and not engaged with the drivetrain for propulsion. In addition, no fuel is supplied to the engine. For ease of reference, this freewheeling mode is denoted as the engine stop freewheeling mode (ES-FM). The engine stop freewheeling mode refers to a freewheeling mode with the engine shutdown, and disconnected from the drive wheel(s).

Operating the powertrain system in the engine stop freewheeling mode ES-FM contributes to even better fuel consumption and reduced emissions. Additionally, the engine stop freewheeling mode ES-FM allows for quicker attainment of the target speed, as compared to other operational modes, such as the coasting mode, wherein the engine remains connected to the driving wheels. The engine stop freewheeling mode ES-FM thus facilitates more efficient acceleration and speed management, particularly in situations such as downhill driving. As such, prolonging the operation of the powertrain system in the engine stop freewheeling mode ES-FM enables the maintenance of a higher average speed.

The disclosure may seek to enhance fuel efficiency in vehicles with powertrain systems configured to be operated in a freewheeling mode with the engine shutdown while the vehicle is in motion, More specifically, the disclosure may seek to managing the challenge of minimizing, or at least reducing, fuel consumption while maintaining operational efficiency and vehicle responsiveness, particularly focusing on the implementation of a freewheeling mode where the internal combustion engine is temporarily shut down and disconnected from the drive wheels to reduce fuel consumption during periods when propulsion is not needed. In this context, it should be noted that the freewheeling mode refers to a mode in which an output shaft of the engine is non-rotating, typically corresponding to an engine shutdown.

A technical benefit may include enhanced fuel efficiency through a more precise management of the freewheeling mode of the powertrain system, in which the proposed computer system provides for predicting when to engage and disengage the freewheeling mode based on the above various dynamic factors to ensure that the benefits of reduced fuel consumption are not offset by the energy costs associated with restarting the engine. By facilitating the timing and conditions under which the freewheeling mode is engaged, the system may minimize, or at least reduce the potential energy loss and mechanical wear associated with frequent transitions between the operational mode, thereby enhancing the overall efficiency and longevity of the powertrain system. In this manner, the proposed computer system allows for the activation of the engine stop freewheeling mode ES-FM based on a more precise estimation of when there is an opportunity for enhancing fuel consumption by operating the powertrain system in the engine stop freewheeling mode ES-FM.

One example of a vehicle comprising a powertrains system and a computer system will now be described in relation to a vehicle in the form of a heavy-duty vehicle, such as a truck.

schematically illustrates an exemplary vehicle. The vehicleincomprises a powertrain system. The powertrain systemis adapted to power the vehicle.

In addition, as depicted in, the vehiclecomprises a computer system. In this example, the powertrain systemcomprises the computer system. In other examples, the computer systemis a separate part of the vehicle, which is configured to be in communication with the powertrain system. The computer systemmay also be a remote server configured to be in communication with the powertrain system. The computer systemis configured to control the powertrain system. The computer systemhere comprises a processing circuitry. The operations of the processing circuitrywill be further described herein. In, the computer systemalso comprises a memoryand a system bus. These components and further optional technical details of the computer systemare described in relation to.

The computer systemis configured to selectively operate the powertrain systemin a number of operational modes, comprising at least the engine stop freewheeling mode ES-FM. In the engine stop freewheeling mode ES-FM. In the engine stop freewheeling mode ES-FM, the output shaft of the engine is non-rotating, and the engine is disconnected from the one or more drive wheels. For ease of reference, the engine stop freewheeling mode ES-FM will in the following be denoted as the freewheeling mode ES-FM.

Optionally, the computer systemis configured to selectively operate the powertrain systemin a number of operational modes, comprising the engine stop freewheeling mode ES-FM, an additional freewheeling mode, denoted as an engine disconnected freewheeling mode (ED-FM), in which an output shaft of the engine is rotating, the engine is disconnected from the one or more drive wheels, and fuel is being supplied to the engine; in a coasting mode CM, in which the output shaft of the engine is rotating, the engine is connected to the one or more drive wheels, and fuel supply to the engine is interrupted; and in an engine braking mode EBM, in which the output shaft of the engine is rotating, the engine is connected to the one or more drive wheels, and the engine is operated so as to generate a braking effect.

In addition, the computer systemis configured to control an engine restart attempt of the vehicle, while the vehicleis moving. The computer systemis thus configured to restart the engineof the vehicle, while the vehicleis moving.

Turning again to, the powertrain systemcomprises an internal combustion engine. For ease of reference, the internal combustion engine is herein typically denoted as the engine, or sometimes as the ICE. The enginecomprises at least one cylinderhaving a combustion chamberand a reciprocating piston. M ore specifically, the enginecomprises a plurality of cylinders, each one having a corresponding combustion chamberand a corresponding pistonarranged therein.

The powertrain systemalso comprises a fuel injector, as illustrated in. The fuel injectoris here an integral part of the engine. The fuel injectoris configured to inject fuel into the engine. The fuel injectormay be any suitable type of injector capable of injecting fuel such as a diesel fuel, a gaseous fuel and the like. Typically, the fuel injectoris arranged in the cylinder, and axially above the piston. Each one of the cylindersof the enginecomprises a corresponding fuel injector. The fuel injectoris controllable by the computer system. By way of example, the fuel injectoris controllable by the processing circuitryof the computer system.

The fuel injectoris controllable by the processing circuitryof the computer systemin order to allow the computer systemto switch between the various modes of the powertrain system, such as the engine stop freewheeling mode ES-FM, as described herein.

The engineis configured to output a rotational speed via an engine output shaft, also referred to as the output shaft of the engine, as illustrated in e.g.. Hence, the powertrain systemcomprises the engine output shaft. The engine output shaftcan either be in a rotating state or in a non-rotating state. When the engine output shaftrotates, the engineis typically turned on, while when the engine output shaftis non-rotating, the engineis typically shutdown.

The engineis typically also configured to operate in a conventional four stroke fashion, i.e. operated by an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke. In this example, the engine is an internal diesel combustion engine, i.e. an engine designed to work according to the diesel process. By way of example, the engineis a compression ignition internal combustion engine. The enginemay also be provided in other types of configurations or be operated by other types of fuels. The components of an engine are well-known, and thus not further described herein.

The powertrain systemhere also comprises a starter motor. The starter motoris here an integral part of the engine. Alternatively, the starter motoris operatively connected to the engineto allow the starter motorto crank the engine, as is commonly known in the art. As such, the starter motoris configured to crank the engine. Engine cranking is performed by controlling the starter motorto engage a flywheel so as to initiate combustion.

Moreover, the powertrain systemcomprises a transmission arrangement. The transmission arrangementcomprises a gearboxand a controllable clutch.

The gearboxhas a number of gear stages to obtain a set of gears. Each one of the gears has a corresponding gear ratio. The transmission arrangementmay sometimes be denoted simply as the transmission.